The Effect of NaCl on the Conformational Behavior of Acenaphthylene Labeled Poly(N,N-diethylacrylamide) in Dilute Aqueous Solution
- Resource Type
- Article
- Authors
- Chen, Yong; Liu, Ming-zhu; Bian, Feng-ling; Wang, Bing; Chen, Shi-lan; Jin, Shu-ping
- Source
- Macromolecular Chemistry and Physics; January 2006, Vol. 207 Issue: 1 p104-110, 7p
- Subject
- Language
- ISSN
- 10221352; 15213935
Summary: The effect of salts on the conformational behavior of acenaphthylene labeled poly(N,N-diethylacrylamide) (PDEA/ACE) has been investigated in dilute aqueous solution using UV-vis and fluorescence spectroscopy. It is demonstrated here that the effectiveness of various salts in changing the lower critical solution temperature (TLCS) of the PDEA/ACE solution followed the Hoffmeister series. The addition of NaCl linearly lowered the TLCS. In dilute aqueous solution, the PDEA/ACE adopted a loose coil conformation below its TLCS. The PDEA/ACE adopted a compact globule conformation above the temperature at which the coil to globule transition (CGT) was completed. A fluorescence anisotropy investigation suggested that a molten globule conformation existed during the CGT of the PDEA/ACE solution. In all of the above three conformations, the PDEA/ACE was more compact in the presence of NaCl than in the absence of any salt.Temperature and NaCl concentration dependence of fluorescence anisotropy of a PDEA/ACE solution. Inset: thermodynamically stable states of PDEA/ACE.